Translations:Benutzer:Arian/Klett-Mini-Test/1596/en

Phosphates are found in sedimentary rocks, but above all in the finest dispersion in crystalline primary rocks in the form of sparingly soluble apatite, a calcium phosphate with traces of fluorine and chlorine. Larger deposits of apatite are mined on the Kola Peninsula, Kirov. Apatite weathers under the action of acids and thereby regenerates the phosphorus balance of the soils. In sedimentary deposits, above all in North Africa, the phosphorites are found. These are slurried-together animal bones from the Tertiary. Ground, they can be applied as a relatively insoluble raw or soft-rock phosphate melioratively on phosphorus-poor sites.